(1) Field of the Invention
The present invention relates to an image display apparatus, and specifically relates to a process in which a plurality of pieces of image data, which are generated by different generators, are transferred therefrom to an image display unit in parallel.
(2) Description of the Related Art
In recent years, camera-equipped mobile-phones have been a main staple of mobile-phones.
FIG. 11 shows an example of the functional structure of a taken-image display system loaded in a camera-equipped mobile-phone.
As shown in FIG. 11, a taken-image display system 1400 includes an image taking unit 1401, an image display unit 1402, and a CPU 1403.
The image taking unit 1401 includes: a lens 1404 used to form an optical image; an image sensor 1405; a signal processing unit 1406; and an image memory 1407.
The image sensor 1405 generates an electric signal in sequence by performing a light-to-electric conversion onto the optical image formed by the lens 1404.
The signal processing unit 1406 sequentially converts the electric signal generated by the image sensor 1405 into image data in a predetermined format (hereinafter, the image data generated by the signal processing unit 1406 is referred to as “natural image data”, and an image represented by the natural image data is referred to as a “natural image”). The signal processing unit 1406 stores at least one screen of image data into the image memory 1407.
The CPU 1403 performs an artificial image data generation process in which it generates image data representing characters, drawings and the like that are to be displayed on a screen together with a natural image (hereinafter, the image data generated by the CPU 1403 is referred to as “artificial image data”, and an image represented by the artificial image data is referred to as an “artificial image”). The CPU 1403 also performs a transmission process in which it transmits the generated artificial image data or the natural image data stored in the image memory 1407 to the image display unit 1402. The CPU 1403 also performs an instruction issuing process in which it issues an instruction such as an image drawing instruction to the image display unit 1402.
The image display unit 1402 performs a drawing process in which it draws a predetermined graphic image in accordance with the image drawing instruction received from the CPU 1403. The image display unit 1402 also performs a composite image generation process in which it generates a composite image from the natural image data and the artificial image data received from the CPU 1403. The image display unit 1402 displays the graphic image and the composite image on a screen.
Meanwhile, in the above-described construction of the taken-image display system 1400, the CPU 1403 performs the transmission process in parallel with other processes. As a result, a transfer of the natural image data or the artificial image data may go into wait state. This prevents the image display unit 1402 from smoothly displaying the natural image, or the main image. That is to say, this prevents display of a high-quality image.